Lock seam joint



United States Patent O 3,332,711 LOCK SEAM JOINT .lohn G. Holly, 732 Cuyler Ave., Oak Park, lll. 60304 Filed Apr. 22, 1964, Ser. No. 361,721 2 Claims. (Cl. 287-189.36)

The present invention relates to lock seam joints and more particularly to joints for securing substantially at sheets of metal together, and still more particularly to a joint fabricated either of low or medium carbon steel, or metal having similar resilient characteristics for providing a well-sealed joint for ordinary purposes and an extraordinarily well-sealed joint when gas-tight or weathertight seals are desired, while being economical to fabricate.

The seal is characterized in being relatively readily assembled with sheets of material that are preformed at their edges simply by rolling substantially continuous beads adjacent and parallel to the edges of the sheets of material to be joined. Most metals have the characteristic of being cold-formed readily by rolling or swedging beads therein and these metals include steel, aluminum, brass, copper, and many other different alloys and base metals.

For use with any particular metal, it is desirable to use a similar metal or a similar alloy for making the lock seam cleat portion of the invention to be described below. For example, if it is desired to copper sheath a roof with soldered joints or caulked joints, or the like, then it is preferable that a suitable resilient copper be used for making the cleat. If aluminum is to be used, a cleat of laluminum is preferred.

However, for the major use of the lock seam joint, to be described in detail below, metals of the iron and steel groups are used, such as black iron sheeting and low carbon sheets for duct work and galvanized low carbon sheets for roofing and siding, etc.

Accordingly, it is a broad object of the invention to provide an improved lock seam joint.

A further object of the invention is to provide a joint that can be made simply at the place of erection of structure made of sheet metal, and the like.

A still further object of the invention is to provide a cleat for a lock seam joint which can be assembled with sheets of metal in different convenient manners to render the use of the cleat substantially universal for joining generally at sheets of metal.

The foregoing and other objects and advantages of the invention will be either obvious or pointed out in the following specification and claims when read in view of the accompanying drawing, in which:

FIGURE 1 is a perspective view of a cleat assembled with a pair of edges of sheet metal to form a lock seam joint;

FIG. 2 is a view of the cleat arranged on the opposite sides of the edges of metal;

FIG. 3 is a sectional view taken on line 3-3 of FIG. l and showing half of a cleat;

FIG. 4 is a View similar to FIG. 3, but showing the half of the cleat with the edge of the sheet metal removed therefrom;

FIG. 5 is a view similar to FIG. 3 showing a modification of the bead in the cleat and the edge of the sheet metal;

FIG. 6 is a view of an edge arranged as in FIG. 2 and including sealing compound between the cleat aud the edge of the sheet metal; and,

FIG. 7 is a diagrammatic view showing one method of assembling the cleat with edges of sheet metal.

Referring now to the drawing and first to FIG. l, a pair of sheets of metal 10 and 11 have edges 12 and 13,

3,332,711 Patented July 25, 1967 rice respectively, in edge facing relationship to each other. Adjacent the edge 12, there is a raised bead 14 which extends parallel to the edge. The other sheet of material 11 has a raised bead 15 adjacent the edge 13 thereof and parallel therewith.

A cleat 17 comprises a base 18 which is shown as substantially flat. However, it is to be understood (-when decorative uses are desired) that the base 18 may be curved or otherwise shaped in keeping with a function of the structure of the cleat 17. The cleat 17 may have additional utility purposes as `by being formed with extensions for securing other structural parts, or the like.

Essentially, the cleat 17 provides the base 18 for spacing apart a pair of intermediate legs 20 and 21, respectively, lying in a common plane, and which legs are bent inwardly toward the center of the base 18 and are substantially parallel therewith. At lapproximately the center of the intermediate legs 20 and 21 are depressed beads 23 and 24, respectively. As will appear more fully below, the depressed beads 23 and 24 are adapted to intimately engage points of the raised beads 14 and 15 substantially along parallel lines to provide a normal seal for the device which has broad utility of itself for sealing air ducts, and the like, without any additional seal.

The inward ends of the intermediate legs 20 and 21 have return bends 25 and 26, respectively, providing outturned legs 29 and 30, respectively, which generally over lie the intermediate legs 20 and 21.

The beads 14 and 15 in the sheet metal edges 10 and 11 can be very conveniently formed by known rolling or swedging equipment which will provide a longitudinal bead which is preferably continuous along and adjacent the edges 12 and 13 of the sheet metal 10 and 11, respectively. By guiding the rolling and swedging operations along the edges 12 and 13, the beads 14 and 15 can be rolled or s-wedged very accurately to provide for very small dimensional deviations between successively formed edges 12 land 13. The cleat 17 can then be conveniently slipped onto one of the edges 12 or 13 longitudinally, or it can be slipped onto both at the same time with the sheets 10 and 11 properly placed. There is still a third method of assembly of this joint which will be described below in yconnection with FIG. 7 for assembling rather thin cross-sectional ducts, or the like, which can be a factory operation or one conveniently performed at the point of erection of a structure made of sheet metal.

FIG. 2 shows the cleat 11 having the base 18 on the top of sheets of material 10a and 11a. The sheets 10a and 11a can be beaded adjacent their edges to form beads 14a and 15a in the same manner as described above in connection with FIG. l. It is to be noted with such arrangement, with the cleat 17 having the base 18 eX- posed or outwardly arranged with respect to the sheets 10a and 11a, that their only points of exposure are edges 18a and 18b of the base 18, whereas in FIGURE 1 there are three lines of exposure including the edges of the outwardly extending legs 29 and 30 and return bends 25 and 26. As will be pointed out below, such external arrangement may be desired for decorative purposes or for weather sealing of the assembly of the lock seam joint.

Referring now to FIG. 3, half of a cleat is shown and like parts bear the same reference characters as in FIG. 1. It is to be noted that the base 18 is suitably spaced at a return bend 35 to provide for substantially horizontal disposition of the intermediate leg 20 while providing clearance for the bottom surface 36 of the depressed bead 23. The upper leg 29 is shown as intimately engaging the surface of sheet metal 10 at the point 38. If it is desired that the formed structure of the lock seam joint be absolutely tight, it is convenient to apply solder or suitable sealant at the point 38. The minimum amount of solder a) will be required to provide sealing of the lock seam joint. It is to be understood that the opposite leg 30 can be then treated likewise as with solder or other suitable sealant to form an inexpensive hermetic seal. It is also to be noted that the raised bead 14 at points 40 and 41 contacts the upper surface of the depressed bead 23.

Referring now to FIG. 4, the half of the cleat 17 described in connection with FIG. 3 is shown in its unassembled form without the sheet in position. It is to be noted that the outer leg 29 is formed to closely approach the intermediate leg 20 adjacent the outermost points thereof. As mentioned above, it is preferred that the metal comprising the cleat 17 be resilient, that is, have a spring constant urging it toward the position shown in FIG. 4. With such resilience, with the cleat 17 assembled with an edge of the sheet metal 10, the beads 14 and 23 will maintain intimate contact at points 40 and 41. For most purposes, this joint is sufficient to prevent appreciable leakage such as might create noise or uneconomical operation of a system wherein heated or chilled air is circulated in ducts.

Referring now to FIG. 5, a sheet of material 10b, as shown, is provided with a V-notch bead 14b which cooperates on its lower surfaces with the inside of a depressed similar V-notch 236. In all other respects, the parts of the `cleat 17b are identical to parts of the cleat 17 described above. The legs of the V-notches 14b and 23h need not be identical in angular relationship with the center of the V, but the left-hand legs of the notches 14b and 23h may be at a substantially steeper angle than the right-hand legs 45 and 46, whereby the force to assemble the sheet 10b with the cleat 17b will be substantially less than the force required to disassemble same to thereby lock the seam in assembled position. Solder 48 is also indicated in this figure for providing a hermetic seal of the assembled parts.

Referring now to FIG. 6, an edge of -a sheet of material such as the right-hand edge 11a as shown in FIG. 2, is illustrated with the cleat 17 secured by means of beads a and 23a. A caulking compound 50, which may be a suitable plastic or a hardening cement, or the like, isl used and this structure is preferred when the lock joint is to be used for roofing. Referring again to FIG. 2, it is to be noted that the high strength base 18 of the cleat 17 is disposed upwardly and is outwardly spaced to provide beam strength for the assembly. For such structure, it may be found desirable to have longitudinal reinforcing corrugations (not shown) included in the base 18 to further augment strength in such strips. With such structure, including that shown in FIG. 2, support joists may be disposed -at greater distances than would be the case without the additional strength of the cleat 17. For such use as a beam or strut, it is preferred that the cleat be made of relatively heavy gauge material having strength attributes and be less resilient while still providing for the ysealing and mechanical locking functions between the beads 15a and 24a, and 14a and 23a.

Referring now to FIG. 7, an assembly method for light gauge metal is readily effected in the following manner: A rectangular duct 52 has a flexible top and side surfaces 53, 54 and 55, and exible bottom surfaces 56 and 57 which may be preformed with an opening adjacent the bottom center position 58. The bottom sheets 56 and 57 can be stressed to bend into substantially the position shown, and the cleat 17 slipped to the left as viewed in FIG. 7 over the beaded edge of the bottom panel 56. Referring to FIG. 4, the edge may be slipped into the entrant notch 60 between the return bend 35 and the extreme end of the overlying leg 29. A slight force may be used to urge the cleat 17 to such an extent that the beads on the edge of the sheet 56 and in the cleat 17 snap together. In this case, it is preferred that the beads be formed substantially as described in connection with FIG. 5 with the legs of the beads 43 and 44 steeper than the legs 45 and 46 so that the resilient outer leg, such as Z9 in FIG. 4, can move away readily under the camming action of the V-leg 45, FIG. 5, While same will snap together when the beads register with each other. The right side beaded edge of the panel 57 can thereafter be slipped into the entrance notch `60 on the right side of the cleat 17 until the beads snap into place to eiect a locked seam joint with a good air seal provided by spring tensioning.

The above cleat and assembled lock seam joint have been described primarily in connection with making longitudinal joints. It is to be understood that transverse joints can also be made in an elongated duct to accommodate ordinary lengths of sheet stock such as used in the trade for fabricating such ducts. In the event the locking feature is desired, it is preferred that the V-type notch, such as described in FIG. 5, be used for transverse joint connections.

While I have shown and described in detail specific embodiments of the invention, obviously modifications thereof will occur to those skilled in the art. Accordingly, I do not wish to be limited in my invention to the details shown and described, but only by the scope of the following claims.

I claim:

1. A lock seam joint comprising a pair of elongated sheets mechanically locked to a cleat, each sheet having an elongated edge having a substantially continuous raised portion extending in parallel spaced relationship with respect to the sheet edge, said cleat being formed fro-rn an elongated sheet of resilient material into a generally flat base leg portion, a first pair of intermediate legs extending laterally from said fiat base leg portion and being rolled and bent back and under the flat base leg portion into generally parallel relationship with respect to each other with the innermost ends of the respective intermediate legs being spaced apart and with the respective intermediate legs being disposed in planes generally parallel to that of the at base leg portion, a second pair of intermediate legs extending in opposite directions fromthe inner spaced apart ends of said first pair of intermediatev legs and being rolled and bent back and under each of the respective intermediate legs of the first pair forming a connecting U-shaped portion between the lirst and second pairs of intermediate legs with the outermost ends of said second pair of intermediate legs being disposed in closer relationship to the iirst pair of intermediate legs than the innermost ends thereof, the bent back portions of the second pair of intermediate legs being generally aligned with and overlying said first pair of intermediate legs, one pair of said intermediate legs being provided with an elongated raised portion spaced between the ends thereof and in substantially parallel relationship with respect to the raised portion of the other leg, the raised portions of the intermediate legs complementing the elongated raised portions on said sheets, each intermediate leg raised portion cooperating with a raised portion on one of said sheets to mechanically lock the sheet to the cleat, each pair of intermediate legs being urged away from each other upon insertion therein of said sheet edges and said raised sheet portions and establishing the releasable compressive mechanical engagement of said intermediate leg raised portions with said sheet raised portions for frictionally and mechanically locking the sheets to the cleat.

2. A lock seam joint comprising an elongated sheet of material being formed into a generally fiat base leg portion, a pair of intermediate legs extending laterally from said base leg portion being rolled and bent back and under the at base leg portion into a generally common plane with respect to each other with the innermost ends of the respective intermediate legs being spaced apart and with the respectiveV intermediate legs being disposed in planes generally parallel to that of the at base leg portion, each of said intermediate legs being provided with an elongated raised portion spaced between the ends thereof with the raised portion of one leg being disposed in substantially parallel relationship with respect to the raised portion of the other leg, the raised portions of the intermediate legs being adapted to complement elongated raised portions on sheet material, each intermediate leg raised portion being adapted to cooperate with a raised portion on sheet material to mechanically lock the sheet material to the cleat, -a pair of outer legs extending in opposite directions from the inner spaced apart legs of said intermediate legs and being rolled and bent back and under with the outermost ends thereof in closer relationship to the intermediate legs than the innermost ends thereof, each respective intermediate leg forming a connecting U-shaped portion between each intermediate and outer leg, the bent back portions of the outer legs being generally aligned with and overlying said intermediate legs and the raised portions carried thereby, a pair of sheets, each having elongated edges, each of the sheets having substantially continuous raised portions disposed in generally parallel spaced relationship with respect to the edges, the sheet edges being inserted between opposed pairs of intermediate and outer legs, each pair of said outer and intermediate legs being urged away from each other upon insertion therein of the sheet edges carrying raised portions and establishing the releasable mechanical engagement of the sheet raised portions with leg raised portions for mechanically locking the sheets to the cleat.

References Cited UNITED STATES PATENTS 933,611 9/ 1909 Zirnmerschied 189--36 1,844,961 2/ 1932 Kramer 189--36 X 2,363,358 11/1944 Punte 189-36 X FOREIGN PATENTS 912,610 12/ 1962 Great Britain.

REINALDO P. MACHADO, Primary Examiner. 

1. A LOCK SEAM JOINT COMPRISING A PAIR OF ELONGATED SHEETS MECHANICALLY LOCKED TO A CLEAT, EACH SHEET HAVING AN ELONGATED EDGE HAVING A SUBSTANTIALLY CONTINUOUS RAISED PORTION EXTENDING IN PARALLEL SPACED RELATIONSHIP WITH RESPECT TO THE SHEET EDGE, SAID CLEAT BEING FORMED FROM AN ELONGATED SHEET OF RESILIENT MATERIAL INTO A GENERALLY FLAT BASE LEG PORTION, A FIRST PAIR OF INTERMEDIATE LEGS EXTENDING LATERALLY FROM SAID FLAT BASE LEG PORTION AND BEING ROLLED AND BENT BACK AND UNDER THE FLAT BASE LEG PORTION INTO GENERALLY PARALLEL RELATIONSHIP WITH RESPECT TO EACH OTHER WITH THE INNERMOST ENDS OF THE RESPECTIVE INTERMEDIATE LEGS BEING SPACED APART AND WITH THE RESPECTIVE INTERMEDIATE LEGS BEING DISPOSED IN PLANES GENERALLY PARALLEL TO THAT OF THE FLAT BASE LEG PORTION, A SECOND PAIR OF INTERMEDIATE LEGS EXTENDING IN OPPOSITE DIRECTIONS FROM THE INNER SPACED APART ENDS OF SAID FIRST PAIR OF INTERMEDIATE LEGS AND BEING ROLLED AND BENT BACK AND UNDER EACH OF THE RESPECTIVE INTERMEDIATE LEGS OF THE FIRST PAIR FORMING A CONNECTING U-SHAPED PORTION BETWEEN THE FIRST AND SECOND PAIRS OF INTERMEDIATE LEGS WITH THE OUTERMOST ENDS OF SAID SECOND PAIR OF INTERMEDIATE LEGS BEING DISPOSED IN CLOSER RELATIONSHIP TO THE FIRST PAIR OF INTERMEDIATE LEGS THAN THE SECOND PAIR OF INTERMEDIATE LEGS BEING GENERALLY OF THE SECOND PAIR OF INTERMEDIATE LEGS BEING GENERALLY ALIGNED WITH AND OVERLYING SAID FIRST PAIR OF INTERMEDIATE LEGS, ONE PAIR OF SAID INTERMEDIATE LEGS BEING PROVIDED WITH AN ELONGATED RAISED PORTION SPACED BETWEEN THE ENDS THEREOF AND IN SUBSTANTIALLY PARALLEL RELATIONSHIP WITH RESPECT TO THE RAISED PORTION OF THE OTHER LEG, THE RAISED PORTIONS OF THE INTERMEDIATE LEGS COMPLEMENTING THE ELONGATED RAISED PORTIONS ON SAID SHEETS, EACH INTERMEDIATE LEG RAISED PORTION COOPERATING WITH A RAISED PORTION ON ONE OF SAID SHEETS TO MECHANICALLY LOCK THE SHEET TO THE CLEAT, EACH PAIR OF INTERMEDIATE LEGS BEING URGED AWAY FROM EACH OTHER UPON INSERTION THEREIN OF SAID SHEET EDGES AND SAID RAISED SHEET PORTIONS AND ESTABLISHING THE RELEASABLE COMPRESSIVE MECHANICAL ENGAGEMENT OF SAID INTERMEDIATE LEG RAISED PORTIONS WITH SAID SHEET RAISED PORTIONS FOR FRICTIONALLY AND MECHANICALLY LOCKING THE SHEETS TO THE CLEAT. 